Recently, with the development of electronic industries and the advance of materials technologies, various electronic devices are designed toward small size, light weightiness and easy portability. Consequently, these electronic devices can be applied to mobile business, entertainment or leisure purposes whenever or wherever the users are. For example, various optical apparatuses are widely used in many kinds of fields such as smart phones, wearable electronic devices or any other appropriate portable electronic devices. Since the electronic devices are small and portable, the users can take the electronic devices to capture images and store the images according to the users' requirements. Alternatively, the images can be uploaded to the internet through mobile networks. In other words, these electronic devices not only have important commercial values but also provide more colorful lives to people.
With the improvement of the living quality, people's demands on more functions of the optical apparatuses of the portable electronic device are extensively increased. Consequently, the portable electronic device brings more convenient functions. For example, the optical apparatus can emit and receive a laser beam to measure a distance of an object from the optical apparatus. Generally, the distance can be quickly measured by a TOF (Time of Flight) measurement method. Regardless of whether the optical apparatus is used to capture 2D or 3D images, perform distance measurement or sense an object, the light collecting efficacy (or the light collection efficiency) of the optical apparatus is one of the important factors influencing the overall quality as well as the processing speed. However, the conventional optical apparatus for increasing the light collecting efficacy cannot be produced in a simple fabricating process and the fabricating cost of the optical apparatus is generally high.
Moreover, the application of the optical apparatus is not restricted to the portable electronic device. For example, Taiwanese Patent No. I477759 discloses an optical detecting apparatus for detecting the physiological parameters of the biological tissue. By a microstructure unit, the energy of a light beam from a light-emitting element is concentrated into a diffractive light in a specified diffractive order. The diffractive light in the specified diffractive order is introduced into a biological tissue that is in contact with the optical detecting apparatus. Then, the light beam scattered and reflected from the biological tissue is guided by a waveguide and transmitted to an optical detecting unit. Consequently, the intensity of the light beam received by the optical detecting unit is increased. However, this optical detecting apparatus is only suitable for the contact-type measurement. Moreover, the microstructure unit is only used to concentrate the energy of the received light beam into the diffractive light in the specified diffractive order. The microstructure unit does not have the function of guiding the light beam.
In other words, the optical apparatus needs to be further improved.